refactor(language): clarify containment hierarchy

1 files changed, 5 insertions, 2 deletions

diff --git a/subprojects/language-ide/src/main/java/tools/refinery/language/ide/syntaxcoloring/ProblemSemanticHighlightingCalculator.java b/subprojects/language-ide/src/main/java/tools/refinery/language/ide/syntaxcoloring/ProblemSemanticHighlightingCalculator.java
index 9c061c8f..477940aa 100644
--- a/subprojects/language-ide/src/main/java/tools/refinery/language/ide/syntaxcoloring/ProblemSemanticHighlightingCalculator.java
+++ b/subprojects/language-ide/src/main/java/tools/refinery/language/ide/syntaxcoloring/ProblemSemanticHighlightingCalculator.java
@@ -20,6 +20,7 @@ import tools.refinery.language.model.problem.ClassDeclaration;
 import tools.refinery.language.model.problem.NamedElement;
 import tools.refinery.language.model.problem.Node;
 import tools.refinery.language.model.problem.PredicateDefinition;
+import tools.refinery.language.model.problem.PredicateKind;
 import tools.refinery.language.model.problem.ProblemPackage;
 import tools.refinery.language.model.problem.ReferenceDeclaration;
 
@@ -99,10 +100,12 @@ public class ProblemSemanticHighlightingCalculator extends DefaultSemanticHighli
                 if (eObject instanceof ClassDeclaration classDeclaration && classDeclaration.isAbstract()) {
                         classesBuilder.add(ABSTRACT_CLASS);
                 }
-                if (eObject instanceof ReferenceDeclaration referenceDeclaration && referenceDeclaration.isContainment()) {
+                if (eObject instanceof ReferenceDeclaration referenceDeclaration
+                                && ProblemUtil.isContainmentReference(referenceDeclaration)) {
                         classesBuilder.add(CONTAINMENT_CLASS);
                 }
-                if (eObject instanceof PredicateDefinition predicateDefinition && predicateDefinition.isError()) {
+                if (eObject instanceof PredicateDefinition predicateDefinition
+                                && predicateDefinition.getKind() == PredicateKind.ERROR) {
                         classesBuilder.add(ERROR_CLASS);
                 }
                 if (eObject instanceof Node node) {